Relapse after a smoking cessation attempt is very rapid. Approximately 25 percent of smokers relapse within the first 24 hours after quitting, 50 percent by 3 days post-cessation, and 75 percent by 2 weeks post-cessation. If relapse could be prevented, we could make substantial progress toward eliminating smoking in this country. Comparatively little is known, however, concerning the relapse phenomenon. Almost nothing is known about early relapse. In a major departure from previous research, which has employed the risk-factor model in studying relapse, we are in the early stages of conducting a study which is investigating the dynamic cognitive (thought) processes associated with relapse, with particular emphasis on understanding early relapse. The central focus in our study is an examination of within-person changes in thinking during the quit attempt. Characterization and understanding of changes in thinking, we and others believe, is a key to understanding the relapse phenomenon. We are requesting additional support to continue the recruitment and 1-month follow-up of 300 adult smokers who plan a serious quit attempt, 101 of whom have completed the study to date. Participants carry hand-held computers and voice tape recorders during their quit attempts. The computers are programmed to beep randomly up to 8 times per day. Participants record their thoughts regarding the quit attempt into the tape recorder, and also respond to closed-ended questions concerning negative and positive affect, withdrawal severity, commitment and motivation levels. The computer/tape recorder responses are providing us with detailed, prospective assessments of participants' thoughts concerning the quit attempt while they are in the community engaging in daily, "real-life" situations. We also plan to recruit and follow 100 Control-group participants who will not carry the computers/tape recorders. Our study is concentrating on understanding changes in thought patterns after quitting, and on how these cognitions relate to the first lapse and subsequent relapse. We believe the study will provide answers to the following questions: (a) why people smoke their first post-cessation cigarette; (b) why people do not return to abstinence after their first cigarette; and (c) how the thinking of successful abstainers differs from the thinking of those who lapse and subsequently relapse. Results should provide a base of knowledge concerning the relapse process from which more effective treatments can be developed to aid smoking cessation.